Jaenichen is a native of Brandenburg, Kentucky, where he attended Meade County High School.

He also served as the commander of Submarine Squadron 11 in San Diego, and deputy chief of legislative affairs for the United States Department of the Navy.

In 2013, Jaenichen was selected to serve as acting United States Maritime Administration by President Barack Obama, succeeding David T. Matsuda.

He also provided testimony to the United States Senate Committee on Commerce, Science, and Transportation, United States House Agriculture Subcommittee on Livestock and Foreign Agriculture, and United States House Transportation Subcommittee on Coast Guard and Maritime Transportation.

[5] In 2017, Jaenichen joined Liberty Global Logistics LLC as an executive vice president.